McLaren Replacement Hospital

Title: McLaren Replacement Hospital

Award Category: Exterior Wall

Project Address/Location

2900 Collins Rd

Lansing, MI 48910
United States

Submitted By: Aaron Rosen

Company Info

RosenBEC

400 Chesterfield Center, #400

Chesterfield, MO 63017
United States

636-3226122

[email protected]

Project Description and Background: The McLaren Greater Lansing Replacement Hospital is a 9-story, 240-bed, 560,000 ft2 building located on Michigan State University’s Corporate Research Park in Lansing, Michigan. During the installation process of the unitized curtain wall panels, the reflected image observed on numerous insulating glass units was brought into question. Upon further review, there was an agreement amongst the project stakeholders that approximately 270 insulating glass units had excessive distortion and required replacement. While there was not a dispute amongst the parties with respect to whether there was indeed a glass-related issue, there was not a consensus regarding the root cause of the problem. As a result, multiple third parties were engaged to review and comment on this distortion issue. There were several types of evaluation techniques utilized which included finite element modeling, air space measurements, and testing in accordance with ASTM glass quality standards. There were varying hypotheses and explanations, thus there was disagreement amongst the project stakeholders with respect to the source of the problem. RosenBEC was tasked with performing an impartial forensic investigation and providing conclusive evidence that explains the excessive distortion observed in the insulating glass units.

Scope: 9 insulating glass units were removed from the project site and then carefully disassembled so the outer lites could be reviewed, independent of other potential contributing factors. A high-quality glass fabricator, that was not affiliated with the project, was tasked with creating baseline control comparison samples in which they heat-treated glass of similar substrate, coating, and size as the project samples that were removed from the building. Concurrently, RosenBEC reviewed the project glass samples using traditional glass evaluation techniques. Interestingly, no issues were identified with any of the glass samples. This included a qualitative visual evaluation using a zebra board as well as a quantitative evaluation for roll wave distortion. An issue with the glass wasn’t apparent until it was viewed from an off angle, which highlighted a typical vertical distortion streak. The project glass and baseline control samples were then electronically scanned. The output from the computer software provided quantitative measurements for a variety of distortion parameters. It also provided 2D and 3D images of the glass samples, highlighting portions of the glass that were not perfectly flat. In addition, the propriety algorithms of the computer software provided quantitative confirmation of an egregious distortion issue with respect to two different quality parameter checks.

Solution: The general contractor hired a testing laboratory to evaluate roll wave distortion. Based on their measurements, they were of the opinion the glass at the project site did not comply with the acceptance criteria. The glass fabricator hired a 3rd party consultant to review the issue at hand. They believed the reported problem was not the result of roll wave distortion, but rather was due to excessive clamping force of the curtain wall pressure plates. They developed their opinion based on finite element computer modeling as well as relying upon another 3rd party, local to the project site, that took field measurements. RosenBEC was then engaged by the glazing contractor to provide another 3rd party opinion. RosenBEC utilized specialized testing equipment and computer software to evaluate the physical characteristics of the glass surface. This technology is commonly used amongst fabricators of high-quality architectural glass, but other parties within the AEC industry might not be as familiar. Not only did this provide electronic measurements of traditional roll wave, but it also scanned the entire surface of the glass for other types of distortion. The results from this testing corresponded with the reported problem observed at the project site and provided conclusive evidence of an issue associated with the glass fabrication process. This allowed the project stakeholders to forego additional time and money with respect to further investigation, but rather proceed with the glass replacement process.

Value: The initial hypotheses developed by the project stakeholders was offered as conjecture. RosenBEC was able to provide indisputable evidence of a vertical distortion streak in the outer lite of the insulating glass units. This distortion streak coincided with the objectionable reflected images that were observed when the glass was installed on the building. The findings from this study were then provided to the glass fabricator so they could take proper corrective action in attempt to minimize the potential for recurrence. There are quality standards for evaluating heat-treated architectural glass. One specific criterion that is typically measured after the heat-treating process is glass bow, which is then evaluated for compliance with an industry recognized glass quality standard. Another common measurement of heat-treated glass is roll wave pattern, which can be compared against criteria that is generally accepted amongst industry professionals. To qualitatively evaluate glass flatness, most high-quality glass fabricators also utilize a zebra board for visual observation. It was proven on this project that the traditional glass evaluation techniques were insufficient to identify the glass distortion issue. Unfortunately, these lites of glass were then used to assemble the insulating glass units, which were then sent overseas to a curtain wall fabricator. After they were glazed into the unitized panels, they were delivered to the project site. Obviously, this was a very costly mishap, estimated at around $500k to investigate the issue, order replacement glass, and re-glaze the units. As a silver lining, the findings from this investigation raised awareness to a variety of stakeholders in which they will be better equipped on future projects when procuring architectural glass. The findings from this investigation were also made available to others in the industry at the 2024 IIBEC Convention and Trade Show, as well as a technical article featured in Interface.

Project Images

Additional Info: This is a very interesting and important topic but not completely understood by all relevant project stakeholders. In my opinion, the industry should come together to develop criteria/guidelines to establish varying levels of quality for architectural glass.

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